Film roll accumulating devices for forming a filmstrip into a film roll are typically used in the film take-up chamber of a camera or in a film cassette.
As discussed in prior art U.S. Pat. No. 3,057,573, patented Oct. 9, 1962, it is desirable for the film take-up chamber of a camera to be expandable to accommodate enlargement of the film roll as additional film is fed into the take-up chamber. Similarly, it is desirable for the supply chamber of a film cassette to be expandable to accommodate enlargement of the film roll as additional film is fed into the supply chamber.
Prior art U.S. Pat. No. 3,718,301, patented Feb. 27, 1973, discloses a film cassette in which an arcuate pressure shoe is slidably mounted in the cassette housing, and a spring urges the pressure shoe toward a front cover of the cassette housing. When the cartridge housing does not contain any film, the arcuate pressure shoe is relatively close to the front cover. When a filmstrip is first fed into the cartridge housing, the arcuate pressure shoe guides the filmstrip into a film roll having a small inside diameter. The pressure shoe is forced backwardly against the urging of the spring as the outside diameter of the film roll is increased by further feeding the filmstrip into the cartridge housing. Thus, the centerpoint or the center axis of the film roll shifts to accommodate enlargement of the film roll.